The present invention generally relates to a window or door construction and more particularly to a flashing for sealing window frames, door frames and the like.
“Flashing” is a term used to identify the methods and devices, which are utilized to prevent water and air infiltration. In recent years, numerous methods and devices have been made in an effort to provide a solution to the problem of water and air infiltration, particularly with regard to windows and doors in either residential or commercial construction. Controlling water and air intrusion is a serious concern and if not done properly may result in damage to the construction. In addition, heat transfer because of air infiltration is a significant factor in reducing the energy efficiency of these buildings. Therefore, a need exists for flashing methods and devices used therein, which can reduce or eliminate the unwanted infiltration of water and/or air while remaining relatively low in cost and easy to use.
In the past, one method for dealing with the potential for water intrusion was to expect that some water will enter the exterior wall openings and therefore, utilize methods and products for flashing that minimize the amount of water/air infiltration while simultaneously allowing water that has infiltrated the construction to be removed by permeating through the flashing. Water vapor permeance is a measure of the amount of water vapor which can permeate or escape through a particular material. The American Society for Testing and Materials (ASTM) has developed a standard test method for water vapor transmission (E-96-00). Generally speaking, a vapor permeance of less than about 0.3 perms is considered a low permeance value, whereas a vapor permeance greater than about 0.4 perms is considered a high permeance value. Therefore, flashing products which provide for the permeation of collected water will typically have a vapor permeance of 0.4 or greater. Such products have been described in U.S. Patent Application Publication No. U.S. 2001/0034984 A1.
In the alternative, a sealed approach has been developed wherein the window or door frames are completely sealed from the exterior environment in an effort to prevent the inward migration of water and air from occurring in the first place. Such barriers are available as Moistop E-Z Seal® from the Fortifiber Corporation of Incline Village, Nev. The Moistop E-Z Seal® has a vapor permeance of less than about 0.3 perms. Additional barriers include Moistop® Flashing (<0.3 perms), Moistop neXT™ Flashing (<0.05 perms) and Fortiflash (<0.08 perms), all available from the Fortifiber Corporation.
The flashing methods and devices heretofore used require on site fabrication and/or additional sealing steps to ensure that the flashing device is properly sealed. These additional steps increase the difficulty of installation as well as increasing costs. Therefore, a need exists for a flashing product which is easy to install, robust, and cost effective.